George Gilmore was shot in the neck in a “ruthless attack in broad daylight” police said
A 32-year-old woman arrested earlier on Sunday has been released.
The PSNI also carried out a search connected to the murder and an ongoing loyalist feud in the Trailcock Road area.
Mr Gilmore, who was 44, was shot in the neck while he was in his car in Cafrrickfergus on Monday afternoon. He died in hospital on Tuesday.
Two men have appeared in court charged with murdering the high-profile loyalist.
Brian Roy McLean, 35, of The Birches, Carrickfergus, and 28-year-old Samuel David McMaw, of Starbog Road, Kilwaughter, appeared at Laganside Court on Saturday.
They were jointly charged with murdering Mr Gilmore on Monday, the attempted murders of two other people on the same day and possessing a firearm and ammunition with intent to endanger life.
In court, both the accused spoke only to confirm their names and that they understood the charge.
There was no application for bail and both were remanded in custody.